Expansion-bolt.



v l L. R. ZIFFERER.

- ExPA'NsloN BOLT. APPLIATION FILED NOV. 25, 1914.-

1,13s,3.45; Patented May 4,1915.

www u LohdrRZff-ergyfp ,Lorimn a. ZIFFERER, or new YORK, N. Y.

EXPANSION -BOLR specification of Letters Patent.

Patented May 4., i915,

Application filed November 25, 1914. Serial No. 873,968.

To all 'a0-fiom t may concern:

Ile' it Vknown that I, Lo'rHAn R. ZIFFERER, a citizen of the UnitedStates, residing at New York, in the county of New York andv State ofNew York, have invented certainv new and useful Improvements inExpansion- Bolts, of which the following is a specification. l

This invention relates to expansion'l bolts formed of a relatively hard.material,-'such as malleable iron, and is concerned with certainexterior and interior features of shield construction.

. My invention has for one of its principal l'objects lthe provision ofelements Aupon the shield exterior. so formed, arranged, and

`sented for convenience as formed of two proportioned as to allow aneasy insertion ofthe device into jits intendedaperture, to resistwithdrawal from the aperture, and

prevent rotary movement within the aperture.

. The invention furtheriis concer-ned with.

the mechanical construction and arrangement ofthese exterior elements tothe end that the forces of compression exerted upon the shield may bestbe withstood.

Other objects and uses will also appear from a detaileddescription ofthe invention as hereinafter set forth.

There are many'materials in which expansion bolts may be anchored.Brick, tile,l concrete, and masonry of all kinds are among the mostcommon. Shields for expansion bolts have heretofore been designed toresist withdrawal from, and rotation within, apertures in materials suchas those mentioned.

So far as I am aware, these ends have not been satisfactorilyaccomplished, due principally, to neglect of factors which are alwayspresent.

It is to provide an expansion bolt the structural elements of which areso arranged as to resist movement and pressure of every kind, that thepresent invention is designed.

In the drawing: lFigure 1 lis a view of an expansion bolt embodying myinvention, shown partially inserted within an aperjture; Fig. 2 is aview similar to Fig, 1, .showing the device completely inserted'withinan aperture;"Fig. 3 is an endview of a slightly modified lform ofdevice' shown inj serted within an aperture; Fig. 4 is an enlargedtransverse section taken on line 4-.4 of Fig. `2.

"'{In the drawing is shown a shieldv repre- -complementary sections 6and 7, held opera-l tively together yat their outer ends by means ofclamps 8, engaging within notches 9.' The disposed transversely lof theshield axis, and

intended to be embedded within the material surrounding the holewhen-expansion is produced. 4It is manifest-that such transverseelements serve primarily to resist longitudi pal movements ofthe shieldwithin its aperure.

Each of the shield sections at its outer end is provided with a numberof projections or longitudinal -ribs 11 of substantially the sameelevation a's the transverse ribs 10. A single projecting fin 12 isarranged symmetrically with respect to the other ribs 1l, this being fgreater' elevation, and prefer-- ably 'inclined as appearsbest in Figs.1 and .2. The disposition of this fin is substantially midway'betweenthe meeting faces of the shield sections. The arrangement shown -in Fig.3 is the same as-in F ig, 2, except that the fin 12 is duplicated on theopposite side of the shield, the other elements remaining the same. e

.Installation of the present expansion bolt within an aperture of properdimensions is readily effected up to the point where. the Further'inser.

ribs 11 encounter the hole. tion is `possible only by forcibly advancingthe shield, as by the use ofa hammer. lIt is manifest that completeinsertion must result in one of two things: either (l) the outer end ofthe shield'must be distorted and' advances.

The use of a pluralityof longitudinal ribs, each intended -to cut aslight furrow intol an aperture has heretofore been suggested,

as I am aware, but this is not a practical construction, as experiencehas demonstrated ico that the numberv of furrows to be so cut mustl bemultiplied so many times as to make such a furrow-cuttingv actionpractically Aimpossible. Alsol I have known of expansion shields,substantially cylindrical at the outer end,uexcept for the provision ofa singleprojecting fin, which shields were found to be unsatisfactorybecause they would be collapsed, ci'ushed, or distorted when' driveninto operative position within apertures. ln

be readily so cut, and to resist successfully the tendency to crush orcollapse the shield sections at theirouter ends.

The purpose of the lribs 11,-it should be explained, is to presentrelatively sharp edges against the interior of the aperture which shall,by a frictional engagement, re sist turning of the shield when a bolt,screw, or lag screw is inserted to cause expansion. The projecting fin12 enhances greatly the resistance against rotation of the shield, bybeing forcibly interlocked within the wall as distinguished from therictional engagement of the ribs 11. It is apparent, of course, that'thepressure exerted on the outer end of the shield by the forcible entry ofthe fin into the anchoring body is distributed to each of the other ribs11, so the pressure of these ribs against the inside of. the aperture isgreatly increased. It appears best from Fig. l that .I have providedaltogether eight longitudinal ribs,

' one of which is the lin 12. This number,

and the disposition of the same .inthe manner illustrated, I prefer toany other. This is due partly to considerations of expediency inmanufacture, and also to the ability of such an arrangementof ribs towithstand stanti ally effectively the pressure resulting trom embedmentof the fin 12 Within the wall. Between these ribs the panels or spacesare flattened to eliminate curvatures in construction. When, fromthedirection of this fin,

forces are exerted inwardly sutlicient to crush, collapse, or distortthe outer end of the shield, the pressure is distributed over the outerend of each'shield half through the straight-line panels which act asbraces, and thrust back against the aperture Walls at seven differentpoints. The distances be tween such points of pressure thrust are soclose, and the material so shaped to serve as bracing elements, thatbending or buckling of the shield cannot take place--a fault hithertocommon in the constructions i I have mentioned.

claim:

An expansion bolt shield having its outer end slightly less in diameter-than the remainder of the shield bo'dy, a projecting fin on the outerend of the shield extended above the `shield body, and other projectionsdisposed parallel lwith the shield axis of subeven height with theshield body, all of the said projections being arranged not more than 45degrees apart, substantially as described.

LOTHAR R. ZIFFERIZR. Witnesses:

P. FRANK SONNEK, H. E. CHAMPION.

